This tool is used quite regularly by our team in our Factory and has saved many disassembly's simply by being able to magnetize a steel rod or thin screwdriver to retrieve a fallen nut or shim.
 
It's great for magnetizing thin wire too that can move a hidden T-nut from behind a plate for positioning. 
 
When you're done simply demagnetize any tools (Screw driver, Allen key, etc.) for metal swarf free use.